WO2020116388A1 - Composé, et matériau de conversion thermoélectrique - Google Patents

Composé, et matériau de conversion thermoélectrique Download PDF

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WO2020116388A1
WO2020116388A1 PCT/JP2019/047017 JP2019047017W WO2020116388A1 WO 2020116388 A1 WO2020116388 A1 WO 2020116388A1 JP 2019047017 W JP2019047017 W JP 2019047017W WO 2020116388 A1 WO2020116388 A1 WO 2020116388A1
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thermoelectric conversion
compound
examples
compounds
graph showing
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PCT/JP2019/047017
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English (en)
Japanese (ja)
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篤典 土居
哲 島野
康二郎 田口
十倉　好紀
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住友化学株式会社
国立研究開発法人理化学研究所
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Priority to JP2020559174A priority Critical patent/JP7148636B2/ja
Priority to CN201980079864.8A priority patent/CN113226981B/zh
Priority to US17/297,213 priority patent/US20220033273A1/en
Publication of WO2020116388A1 publication Critical patent/WO2020116388A1/fr

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/851—Thermoelectric active materials comprising inorganic compositions
    • H10N10/852—Thermoelectric active materials comprising inorganic compositions comprising tellurium, selenium or sulfur
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G45/00—Compounds of manganese
    • C01G45/006—Compounds containing, besides manganese, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B19/00—Selenium; Tellurium; Compounds thereof
    • C01B19/04—Binary compounds including binary selenium-tellurium compounds
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C13/00—Alloys based on tin
    • C22C13/02—Alloys based on tin with antimony or bismuth as the next major constituent
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/10—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects
    • H10N10/17—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects characterised by the structure or configuration of the cell or thermocouple forming the device
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/81—Structural details of the junction
    • H10N10/817—Structural details of the junction the junction being non-separable, e.g. being cemented, sintered or soldered

Definitions

  • the present invention relates to compounds and thermoelectric conversion materials.
  • the present application claims priority based on Japanese Patent Application No. 2018-227569 filed on Dec. 4, 2018, and the content thereof is incorporated herein.
  • thermoelectric conversion devices that utilize the exhaust heat of automobiles and factory exhaust heat, which correspond to the heat source in the high temperature range, are being studied.
  • thermoelectric conversion material that constitutes the thermoelectric conversion device is required to have high heat resistance.
  • Non-Patent Document 1 a compound containing Sn, Te, and Mn as constituent elements has been reported.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide a compound having thermoelectric conversion characteristics and high heat resistance, and a thermoelectric conversion material containing the compound.
  • the present invention includes the following aspects.
  • [1] A compound containing Sn, Te and Mn and further containing either one or both of Sb and Bi.
  • the compound is further Mg, In, Na, Al, Si, K, Ca, Sr, Ba, Cu, Ag, Au, Sc, Ti, V, Cr, Fe, Co, Ni, Zn, Ga. , Ge, As, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, Cs, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm. , Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Hg, Tl, Pb, S, Se, Cl, Br and I containing at least one element [1] Alternatively, the compound according to [2].
  • M is Mg, Na, Al, Si, K, Ca, Sr, Ba, Cu, Ag, Au, Sc, Ti, V, Cr, Fe, Co, Ni, Zn, Ga, Ge, As, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, Cs, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, It represents at least one element selected from the group consisting of Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Hg, Tl and Pb.
  • X represents at least one element selected from the group consisting of S, Se, Cl, Br and I.
  • a, b, c1, c2, d, e and f are ⁇ 0.05 ⁇ a ⁇ 0.10, 0 ⁇ b ⁇ 0.15, 0 ⁇ c1 ⁇ 0.10, 0 ⁇ c2 ⁇ 0.10, It is a number that satisfies 0 ⁇ d ⁇ 0.03, 0 ⁇ e ⁇ 0.20 and 0 ⁇ f ⁇ 0.20. However, 0 ⁇ c1+c2. )
  • thermoelectric conversion material containing the compound according to any one of [1] to [5].
  • thermoelectric conversion characteristics and high heat resistance thermoelectric conversion characteristics and high heat resistance
  • thermoelectric conversion material containing the compound thermoelectric conversion material
  • thermoelectric conversion element which has the thermoelectric conversion material of this embodiment as a forming material
  • thermoelectric conversion device which has a thermoelectric conversion element.
  • thermoelectric conversion module which has the thermoelectric conversion device of this embodiment.
  • 1 is a powder X-ray diffraction pattern of the compound of Example 1.
  • 4 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • 5 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • 3 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • 5 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 2 and 4.
  • 5 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 2 and 4.
  • 3 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 2 and 4. It is a graph which shows the temperature dependence of the output factor (PowerFactor) of the compounds of Examples 2 and 4. 3 is a graph showing the temperature dependence of zT of the compounds of Examples 2 and 4. 3 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • 5 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • 5 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Example 2 and Comparative Example 1.
  • 3 is a graph showing the temperature dependence of zT of the compounds of Example 2 and Comparative Example 1.
  • 5 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • 5 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • 3 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • 4 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • 3 is a graph showing the temperature dependence of zT of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • 5 is a graph showing the results of heat resistance evaluation of the compound of Example 4.
  • 5 is a graph showing the results of heat resistance evaluation of the compound of Comparative Example 1.
  • thermoelectric conversion characteristic means the property of converting thermal energy into electric energy by the Seebeck effect, thermomagnetic effect, spin Seebeck effect, or the like.
  • thermoelectric conversion physical properties means physical properties related to thermoelectric conversion performance index and output factor, which are thermoelectric conversion performance of thermoelectric conversion materials. More specifically, “thermoelectric conversion properties” mean Seebeck coefficient, resistivity, and thermal conductivity.
  • thermoelectric conversion performance index and an output factor are used as an index of thermoelectric conversion performance of a thermoelectric conversion material.
  • thermoelectric conversion performance index is an index of thermal efficiency of thermoelectric conversion by the thermoelectric conversion material.
  • the above thermal efficiency is represented by the following formula.
  • the maximum thermal efficiency ⁇ opt obtained is represented by the following formula (1).
  • T H is the temperature of the hot end of an object formed by the thermoelectric conversion material [unit: K]
  • T C is the temperature of the cold end of an object formed by the thermoelectric conversion material [unit: K]
  • T ave is the average [unit: K] of T H and T C
  • Z is the average value [1/K] of the thermoelectric conversion performance index z of the thermoelectric conversion material in the temperature region.
  • the “high-temperature end” refers to a relatively high temperature part of the two parts that give a temperature difference used for thermoelectric conversion in the object formed of the thermoelectric conversion material.
  • the “low temperature end” refers to a relatively low temperature part of the two parts that give a temperature difference used for thermoelectric conversion in the object formed of the thermoelectric conversion material.
  • thermoelectric conversion performance index z[1/K] of the thermoelectric conversion material at a certain temperature T is represented by the following formula (2).
  • ⁇ is the Seebeck coefficient [V/K] of the thermoelectric conversion material at a certain temperature T
  • ⁇ is the resistivity [ ⁇ m] of the thermoelectric conversion material at a certain temperature T
  • ⁇ is the thermoelectric conversion at the certain temperature T.
  • the thermal conductivity [W/(m ⁇ K)] of the material is shown.
  • thermoelectric conversion material is desired to exhibit a high thermoelectric conversion performance index z in a wide temperature range.
  • the output factor is an index of electric power that can be output by thermoelectric conversion when thermoelectric conversion is performed using an object formed of a thermoelectric conversion material.
  • the product of the square of the Seebeck coefficient and the reciprocal of the resistivity expressed by the following formula (3) is an index representing the power that can be output by thermoelectric conversion.
  • the index expressed by the equation (3) is called an output factor [W/(m ⁇ K 2 )].
  • the output factor is sometimes called the Power Factor.
  • the output factor represented by the above formula (3) is an index of the maximum power that can be output when a certain temperature difference is applied to both ends of the object formed of the thermoelectric conversion material.
  • the output factor is a measure of the maximum electric power that can be output when the thermoelectric conversion device configured using the thermoelectric conversion material is operated under constant conditions. It is shown that the larger the power factor is, the larger the maximum electric power output obtained by the thermoelectric conversion device configured by using the thermoelectric conversion material is.
  • the heat resistance of the thermoelectric conversion material is based on the absolute value of the rate of change of the resistivity of the thermoelectric conversion material due to heating and cooling.
  • the resistivity is a property that easily reflects the thermal history due to heating and cooling.
  • the thermoelectric conversion material is required to have a small absolute value of the rate of change in resistivity of the thermoelectric conversion material due to heating and cooling.
  • the “main phase” means a phase having a main peak with the highest intensity when the main peaks of the phases identified from the X-ray diffraction pattern are compared.
  • the X-ray diffraction pattern contains a plurality of peaks, and for each peak, the corresponding phase can be identified by a known method such as the Hanawald method. From the X-ray diffraction pattern, it can be seen that the compound has a single phase or multiple phases. There is a main peak in each of the identified phases.
  • the “main peak” means a peak having the highest intensity in a peak group belonging to one phase.
  • the compound of the present embodiment contains Sn, Te and Mn, and further contains one or both of Sb and Bi.
  • the compound of the present embodiment is a compound having a small absolute value of the rate of change in resistivity upon heating and cooling, and has SnTe as a main phase, contains one or both of Sb and Bi, and further contains Mn. It is preferable to contain Hereinafter, they will be described in order.
  • the crystal structure of the compound of the present embodiment can be evaluated, for example, from a powder X-ray diffraction pattern obtained by using a powder X-ray diffraction measuring device.
  • the compound of the present embodiment preferably has a crystal structure of SnTe as a main phase.
  • the crystal structure of SnTe is a cubic crystal of space group Fm-3m at 25°C.
  • the compound of the present embodiment has a crystal structure of SnTe and is a compound having SnTe as a main phase
  • the cubic of the TeTe space group Fm-3m The intensity of the main peak of the crystal structure of the crystal is the strongest among the main peaks of each phase.
  • the ratio of the peak intensity of the main peak of the main phase of the compound to the total peak intensity of the main peaks of all the phases included in the crystal structure of the compound 50% or more, more preferably 70% or more, still more preferably 90% or more.
  • the absolute value of the rate of change in resistivity due to heating and cooling is further reduced. Therefore, the thermoelectric conversion material containing the compound of this embodiment has excellent heat resistance.
  • composition distribution of compound The composition of the compound can be evaluated based on the composition distribution map obtained by preparing a composition distribution map of the evaluation sample using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Specifically, the composition of the compound is evaluated under the condition that the composition distribution of 0.2 ⁇ m or more can be clearly identified.
  • the energy dispersive X-ray spectrometer may be abbreviated as EDX.
  • the scanning electron microscope may be abbreviated as SEM.
  • the longest diameter of the crystal of each element unevenly distributed in the compound is 20 ⁇ m or less.
  • the “longest diameter of a crystal” can be calculated from an SEM image, and means the longest diameter among the diameters (lengths) of individual portions on the individual two-dimensional cross-sections of crystals of each element unevenly distributed in the compound. To do.
  • the compound of the present embodiment contains Sn, Te and Mn, and further contains one or both of Sb and Bi.
  • the carrier density in the compound can be adjusted appropriately. Therefore, the Seebeck coefficient is improved.
  • Mn adjusts the band structure of the valence band of the compound and improves the Seebeck coefficient of the compound.
  • thermoelectric conversion material containing the compound of this embodiment has excellent heat resistance.
  • the above element is preferably at least one element selected from the group consisting of Cu, In and Se.
  • the element may be contained alone or in combination of two or more.
  • the compound of this embodiment is preferably a compound represented by the following formula (A).
  • the compound represented by the following formula (A) is a compound having a small absolute value of the rate of change in resistivity during heating and cooling. Sn 1 + a-b-c1 -c2-d-e Mn b Bi c1 Sb c2 In d M e Te 1-f X f ...
  • M is Mg, Na, Al, Si, K, Ca, Sr, Ba, Cu, Ag, Au, Sc, Ti, V, Cr, Fe, Co, Ni, Zn, Ga, Ge, As, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, Cs, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, It represents at least one element selected from the group consisting of Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Hg, Tl and Pb.
  • X represents at least one element selected from the group consisting of S, Se, Cl, Br and I.
  • a, b, c1, c2, d, e and f are 0 ⁇ a ⁇ 0.10, 0 ⁇ b ⁇ 0.15, 0 ⁇ c1 ⁇ 0.10, 0 ⁇ c2 ⁇ 0.10, 0 ⁇ d It is a number that satisfies ⁇ 0.03, 0 ⁇ e ⁇ 0.20, and 0 ⁇ f ⁇ 0.20. However, 0 ⁇ c1+c2. )
  • a is preferably 0 ⁇ a ⁇ 0.10, more preferably 0.02 ⁇ a ⁇ 0.08, and further preferably 0.03 ⁇ a ⁇ 0.07.
  • a is included in these numerical ranges, either or both of the Seebeck coefficient and the electric conductivity of the compound of the present embodiment are improved. Therefore, the thermoelectric conversion performance index z of the compound represented by the formula (A) is improved.
  • the upper limit value and the lower limit value of a can be arbitrarily combined.
  • the substance amount of Mn in the compound represented by the formula (A) is represented by b in the formula (A).
  • b is preferably 0 ⁇ b ⁇ 0.15, more preferably 0.04 ⁇ b ⁇ 0.13, and further preferably 0.07 ⁇ b ⁇ 0.12.
  • the band structure of the compound is appropriately adjusted and the Seebeck coefficient is increased. Therefore, the thermoelectric conversion performance index z of the compound is improved.
  • the upper limit value and the lower limit value of b can be arbitrarily combined.
  • the substance amount of Bi in the compound represented by the above formula (A) is represented by c1 in the above formula (A).
  • c1 is preferably 0 ⁇ c1 ⁇ 0.10, more preferably 0 ⁇ c1 ⁇ 0.07, further preferably 0.005 ⁇ c1 ⁇ 0.07, and 0.01 ⁇ c1 ⁇ 0. 06 is even more preferable.
  • the substance amount (c1) of Bi when included in these numerical ranges, a compound having a small absolute value of the rate of change in resistivity during heating and cooling can be obtained.
  • the upper limit value and the lower limit value of c1 can be arbitrarily combined.
  • the substance amount of Sb in the compound represented by the formula (A) is represented by c2 in the formula (A).
  • c2 is preferably 0 ⁇ c2 ⁇ 0.10, more preferably 0.005 ⁇ c2 ⁇ 0.07, and further preferably 0.01 ⁇ c2 ⁇ 0.06. Further, in the formula (A), c2 may be 0 ⁇ c2 ⁇ 0.07 or 0 ⁇ c2 ⁇ 0.06.
  • the substance amount (c2) of Sb when the substance amount (c2) of Sb is included in these numerical ranges, a compound having a small absolute value of the rate of change in resistivity during heating and cooling can be obtained.
  • the upper limit value and the lower limit value of c2 can be arbitrarily combined.
  • the substance amount of In in the compound represented by the formula (A) is represented by d in the formula (A).
  • d is preferably 0 ⁇ d ⁇ 0.03, more preferably 0.002 ⁇ d ⁇ 0.02, and further preferably 0.004 ⁇ d ⁇ 0.015. Further, in the formula (A), d may be 0 ⁇ d ⁇ 0.02 or 0 ⁇ d ⁇ 0.015.
  • the upper limit value and the lower limit value of d can be arbitrarily combined.
  • the element M is at least selected from the group consisting of Mg, Cu and Ag from the viewpoint of improving the thermoelectric conversion performance index z of the compound represented by the formula (A).
  • One element is preferable, and Cu is more preferable.
  • the compound of the present embodiment preferably has SnTe as the main phase and contains Bi, Mn and Cu.
  • the absolute value of the rate of change in resistivity due to heating and cooling is small. Therefore, the thermoelectric conversion material containing the compound of this embodiment has excellent heat resistance.
  • e is preferably 0 ⁇ e ⁇ 0.10 in the formula (A) from the viewpoint of appropriate control of physical properties, and 0. 005 ⁇ e ⁇ 0.07 is more preferable, and 0.005 ⁇ e ⁇ 0.05 is further preferable. Further, in the above formula (A), e may be 0 ⁇ d ⁇ 0.07 or 0 ⁇ d ⁇ 0.05. The upper limit value and the lower limit value of e can be arbitrarily combined.
  • the amount of Mg in the compound is less than or equal to the amount of Mn in the compound.
  • e is preferably 0 ⁇ e ⁇ 0.10 in the formula (A) from the viewpoint of improving the thermoelectric conversion performance index z, and 0. 005 ⁇ e ⁇ 0.07 is more preferable, and 0.005 ⁇ e ⁇ 0.05 is further preferable.
  • the upper limit value and the lower limit value of e can be arbitrarily combined.
  • the element M may be contained alone or in combination of two or more.
  • the element X includes at least one element selected from the group consisting of S, Se, Cl, Br and I.
  • f is preferably 0 ⁇ f ⁇ 0.20, more preferably 0.02 ⁇ f ⁇ 0.15, and further preferably 0.04 ⁇ f ⁇ 0.10.
  • the carrier density described later can be controlled in an appropriate range, so that the thermoelectric conversion performance index z is improved.
  • the upper limit value and the lower limit value of f can be arbitrarily combined.
  • the compound represented by the formula (A) preferably contains, as the element X, one or both of Se and S.
  • the compound represented by the formula (A) contains Se or S as the element X, it has an effect of lowering the thermal conductivity of the compound, and can improve the thermoelectric conversion performance index z of the compound. Become.
  • the element X may be contained alone or in combination of two or more.
  • examples of preferable combinations of the numerical ranges of a, b, c1, c2, d, e and f are 0.02 ⁇ a ⁇ 0.08 and 0.04 ⁇ b. ⁇ 0.13, 0 ⁇ c1 ⁇ 0.07, 0 ⁇ c2 ⁇ 0.10, 0 ⁇ d ⁇ 0.03, 0 ⁇ e ⁇ 0.10, 0 ⁇ f ⁇ 0.20.
  • a carrier is an electron or a hole.
  • the carrier density indicates the amount of electrons or holes (holes) present in a compound per unit volume.
  • the carrier density of the compound of the present embodiment increases the Seebeck coefficient within the range where the resistivity of the thermoelectric conversion material containing the compound does not increase too much, and improves the output factor of the compound and the thermoelectric conversion performance index z. It is preferably not more than 0.0 ⁇ 10 20 cm ⁇ 3 . Since the thermoelectric conversion performance index z is improved, the carrier density of the compound represented by the formula (A) is more preferably 0.5 ⁇ 10 20 cm ⁇ 3 or more and 4.0 ⁇ 10 20 cm ⁇ 3 or less, and 0 or less. It is more preferably 0.8 ⁇ 10 20 cm ⁇ 3 or more and 2.5 ⁇ 10 20 cm ⁇ 3 or less.
  • the carrier density of a compound can be controlled by changing the composition ratio of the elements contained in the compound. Further, the carrier density of the compound can be controlled by replacing the element contained in the compound with another element. In controlling the carrier density of the compound, changing the composition ratio of the element contained in the compound and replacing the element contained in the compound with another element may be combined.
  • the carrier density can be further reduced, for example, by substituting a part of Sn in the compound with Bi or Sb.
  • the carrier density can be further reduced.
  • a physical property measuring device PPMS manufactured by Quantum Design
  • a 5-terminal hole measurement using a dedicated DC resistance sample pack can be used.
  • the hole measurement can be performed by stabilizing the temperature of the sample to be measured and applying a magnetic field perpendicular to one surface of the sample to measure the hole resistance.
  • the Hall coefficient can be calculated from the slope of the Hall resistance with respect to the magnetic field, and the carrier density can be calculated from the Hall coefficient.
  • the Seebeck coefficient at each temperature of the compound of this embodiment is preferably in the following range from the viewpoint of improving the thermoelectric conversion performance index z and the output factor, which are the values represented by the formula (2).
  • the Seebeck coefficient [ ⁇ V/K] at 100°C is preferably 60 or more. It is more preferably 70 or more.
  • the Seebeck coefficient [ ⁇ V/K] at 200°C is preferably 90 or more. It is more preferably 100 or more, still more preferably 110 or more.
  • the Seebeck coefficient [ ⁇ V/K] at 300°C is preferably 120 or more. It is more preferably 130 or more, still more preferably 140 or more.
  • the Seebeck coefficient [ ⁇ V/K] at 400°C is preferably 150 or more. It is more preferably 170 or more, still more preferably 180 or more.
  • the Seebeck coefficient [ ⁇ V/K] at 500°C is preferably 180 or more. It is more preferably 190 or more, still more preferably 200 or more.
  • the Seebeck coefficient can be controlled by replacing the element contained in the compound of the present embodiment with another element.
  • the band structure of the valence band of SnTe can be adjusted by replacing a part of Sn in the compound of the present embodiment with Mn. At that time, by replacing a part of Sn with Mn in an appropriate amount, the band structure of the valence band is adjusted, the density of states near the Fermi level is increased, and the Seebeck coefficient of the compound of this embodiment is improved.
  • the “appropriate amount” is, for example, 10% of the substance amount of Sn.
  • the resonance level of the compound of this embodiment can be formed in the vicinity of the Fermi level. Thereby, the density of states near the Fermi level is increased, and the Seebeck coefficient of the compound of this embodiment is improved.
  • the amount replaced by In is, for example, 1% of the amount of Sn substance.
  • the carrier density can be controlled and the Seebeck coefficient of the compound can be improved.
  • a part of Sn in the compound is replaced with one or both of Sb and Bi, and a part of Sn in the compound of the present embodiment is further replaced. Is preferably replaced by either one or both of Mn and In.
  • the raw materials containing Sn, Mn and Te, and either or both elements of Sb and Bi are mixed and heated at 780° C. or higher to be melted to form a melt.
  • the step of obtaining a melt is referred to as “melting step”
  • the step of quenching is referred to as “quenching step”.
  • Examples of raw materials used in the melting step include metals, metal salts, and nonmetals.
  • Examples of the shape of the raw material include powder, particles, and ingots.
  • the metal examples include Sn, Mg, Bi, Sb, Mn, In, Na, Al, Si, K, Ca, Sr, Ba, Cu, Ag, Au, Sc, Ti, V, Cr, Fe, Co and Ni. , Zn, Ga, Ge, As, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, Cs, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho. , Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Hg, Tl and Pb. These metals may be used alone or in combination of two or more.
  • the metal salt examples include metal salts having the metal as a metal cation.
  • the counter anion of the metal salt is not particularly limited, but examples thereof include a halide ion of Br ⁇ , Cl ⁇ , I ⁇ or F ⁇ and an anion of Group 16 of S 2 ⁇ , Se 2 ⁇ or Te 2 ⁇ .
  • nonmetal simple substance of S, Se or Te can be mentioned.
  • composition ratio (molar ratio) of each element contained in the raw materials according to the composition ratio of the final product compound.
  • the maximum temperature during heating in the melting process is 780°C or higher.
  • the maximum temperature during heating is preferably 900° C. or higher because the composition distribution of the obtained melt tends to approach uniform.
  • the melting method is not particularly limited, and examples thereof include heating by a resistance heating element, heating by a high frequency induction furnace, arc melting, electron beam melting and the like.
  • the raw materials In order to prevent the above raw materials and the melt obtained in the melting step from being altered, it is preferable to heat the raw materials in an inert atmosphere such as argon, nitrogen or vacuum in the melting step.
  • the raw material In the melting step, the raw material may be filled in an ampoule tube whose inside is replaced with an inert atmosphere and heated.
  • the inner wall of the ampoule tube may be coated with carbon in order to prevent the raw material from reacting with the ampoule tube.
  • the quenching step of the present embodiment it is preferable to rapidly cool the melt obtained in the melting step to 100°C or lower. Specifically, in the cooling step, the melt is preferably cooled to 100° C. or lower within 10 minutes, more preferably within 5 minutes, and further preferably within 1 minute.
  • a liquid having a boiling point of 100° C. or less such as water, liquid air or liquid nitrogen, can be used.
  • Water is preferable because it is inexpensive and highly safe.
  • Mn, Bi, and Sb can be solid-dissolved in the crystal lattice of the main phase SnTe in a supersaturated state.
  • the output factor of the thermoelectric conversion material containing the compound is improved.
  • the method for producing the compound in the second embodiment cools the melt obtained in the above-mentioned melting step without quenching, and contains at least one of Sn, Mn and Te, and/or Sb and Bi.
  • the method includes a step of obtaining a material, a step of pulverizing the obtained material to obtain a material powder, and a step of sintering the material powder at 400° C. or higher using a plasma sintering method.
  • the step of obtaining a material is called a “material manufacturing step”
  • the step of obtaining a material powder is called a “powdering step”
  • the step of sintering the material powder is called a “plasma sintering step”.
  • melt obtained in the melting process is cooled to 100° C. or lower over 10 minutes without using the liquid.
  • the material obtained in the material manufacturing step is crushed into powder by a ball mill or the like.
  • the particle size of the powdered fine particles is not particularly limited, but is preferably 150 ⁇ m or less.
  • Pulsma sintering process In the plasma sintering step, a pulsed current is passed through the material powder while pressing the material powder obtained in the powderizing step. As a result, electric discharge occurs between the material powders, and the material powders can be heated and sintered.
  • the plasma sintering step is preferably performed in an inert atmosphere such as argon, nitrogen, or vacuum in order to prevent the resulting compound from deteriorating due to contact with air.
  • the pressure applied in the plasma sintering process is preferably in the range of more than 0 MPa and 100 MPa or less.
  • the pressure applied in the plasma sintering step is preferably 10 MPa or higher, more preferably 30 MPa or higher.
  • the heating temperature in the plasma sintering step is preferably sufficiently lower than the melting point of the target compound, and is preferably 700° C. or lower.
  • the heating temperature in the plasma sintering step is more preferably 650°C or lower.
  • the heating temperature in the plasma sintering step is preferably 400° C. or higher, and more preferably 500° C. or higher in order to promote sintering.
  • the upper limit value and the lower limit value of the heating temperature in the plasma sintering step can be arbitrarily combined.
  • the plasma sintering step in the obtained compound, in order to suppress uneven distribution of elements contained in the obtained compound, it is preferable to stop the energization and cool after heating at the heating temperature.
  • the material is rapidly cooled by including the plasma sintering step, and Mn, Bi, and Sb are solid-solved in the crystal lattice of SnTe, which is the main phase, in a supersaturated state.
  • the raw materials containing Sn, Mn and Te, and either or both elements of Sb and Bi are mixed and heated at 780° C. or higher to be melted to form a melt.
  • a step of sintering the material powder at a temperature of 400° C. or higher using a binding method plasma sintering step.
  • the melting step, the quenching step, the powdering step, and the plasma sintering step in the present embodiment the melting step, the quenching step, and the second step of the compound manufacturing method in the first embodiment of the compound manufacturing method are described. This is the same as the description in the powdering step and the plasma sintering step in the embodiment.
  • the method for producing the compound the method for producing the compound of the third embodiment is preferable. Since the manufacturing method of the third embodiment uses the quenching step and the plasma sintering step in combination, Mn, Bi and Sb are sufficiently supersaturated in the crystal lattice of SnTe which is the main phase of the obtained compound. Can be dissolved. As a result, the electrical conductivity of the compound obtained by the method for producing the compound is improved, and the output factor of the obtained compound is improved.
  • the above compounds will be compounds that have a high power factor in the high temperature range.
  • thermoelectric conversion material in the present embodiment is a material having the thermoelectric conversion characteristics, including the compound of the present embodiment described above.
  • the thermoelectric conversion material in the present embodiment may contain one kind of the compound of the present embodiment described above, or may contain two or more kinds.
  • the content of the compound of the present embodiment in the thermoelectric conversion material is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, and 80% by mass or more and 100% by mass or less. Is more preferable, and 90% by mass or more and 100% by mass or less is even more preferable.
  • the thermoelectric conversion material if the content ratio of the compound of the present embodiment described above is within the above range, the thermoelectric conversion material has a high thermoelectric conversion performance index z.
  • thermoelectric conversion material may include, for example, a polymer compound, glass, ceramics and the like in addition to the compound of the present embodiment described above.
  • the polymer compound that can be contained in the thermoelectric conversion material is not particularly limited, but acrylic resin, terephthalate resin, engineering plastic, fluororesin, polyethylene, polypropylene, epoxy resin, diallyl phthalate resin, silicone resin, phenol resin, polyester resin. , Polyimide resin, polyurethane resin and melamine resin.
  • thermoelectric conversion material is not particularly limited, and examples thereof include quartz glass, borosilicate glass, and alkali-free glass.
  • thermoelectric conversion material can include are not particularly limited, but include alumina, titania, zirconia, silicon nitride, silicon carbide, cordierite, ferrite, barium titanate, lead zirconate titanate, forsterite, zircon, and mullite. , Aluminum nitride, mica, boron nitride, titanium carbide and zinc oxide.
  • thermoelectric conversion material as described above uses a compound whose resistivity changes little before and after heating and cooling, it becomes a thermoelectric conversion material with excellent thermal efficiency in the high temperature region.
  • FIG. 1 is a schematic cross-sectional view of a thermoelectric conversion element including the thermoelectric conversion material described above as a forming material and a thermoelectric conversion device including the thermoelectric conversion element.
  • thermoelectric conversion element is an element that converts thermal energy into electric energy by utilizing Seebeck effect, thermomagnetic effect, spin Seebeck effect, and the like.
  • thermoelectric conversion device 10 shown in FIG. 1 has a p-type thermoelectric conversion element 11, an n-type thermoelectric conversion element 12, a high temperature side electrode 15 and a low temperature side electrode 16.
  • the low temperature side electrode 16 includes an electrode 161 and an electrode 162.
  • thermoelectric conversion element the side where the high temperature side electrode 15 is arranged in the thermoelectric conversion device 10 is "upper” and the side where the low temperature side electrode 16 is arranged is “lower”, and the relative position of each member may be explained. ..
  • “upper” of “upper” and “lower” of “lower end” have the same meaning.
  • thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 when collectively referred to, they may be simply referred to as “thermoelectric conversion element”.
  • the p-type thermoelectric conversion element 11 has a thermoelectric conversion layer 111. Further, as shown in the figure, the p-type thermoelectric conversion element 11 may have a bonding layer 112 and a diffusion prevention layer 113.
  • the thermoelectric conversion layer 111 is an element that generates a thermoelectromotive force when positively charged holes (h + ) move from a high temperature portion to a low temperature portion when a temperature difference occurs in the element.
  • the thermoelectric conversion layer 111 has a p-type electronic physical property and is formed using a thermoelectric conversion material having a positive Seebeck coefficient.
  • the thermoelectric conversion layer 111 is obtained by machining the thermoelectric conversion material of the present embodiment described above into a desired shape.
  • the thermoelectric conversion layer 111 has a columnar shape.
  • the bonding layer 112 is provided between the thermoelectric conversion layer 111 and the high temperature side electrode 15.
  • the bonding layer 112 satisfactorily electrically and mechanically bonds the thermoelectric conversion layer 111 and the high temperature side electrode 15. Thereby, the bonding layer 112 reduces the contact resistance between the thermoelectric conversion layer 111 and the high temperature side electrode 15.
  • the bonding layer 112 is provided between the thermoelectric conversion layer 111 and the electrode 161 (low temperature side electrode 16).
  • the bonding layer 112 bonds the thermoelectric conversion layer 111 and the electrode 161 favorably electrically and mechanically. Thereby, the bonding layer 112 reduces the contact resistance between the thermoelectric conversion layer 111 and the electrode 161.
  • thermoelectric conversion element As the material for forming the bonding layer 112, an element that increases the carrier density of the thermoelectric conversion element can be mentioned, and silver, gold and platinum are preferable.
  • the thickness of the bonding layer 112 is not particularly limited, but is preferably 0.001 ⁇ m or more and 20 ⁇ m or less, more preferably 0.005 ⁇ m or more and 10 ⁇ m or less.
  • the upper limit value and the lower limit value of the thickness of the diffusion prevention layer 113 can be arbitrarily combined.
  • the diffusion prevention layer 113 is provided between the thermoelectric conversion layer 111 and the bonding layer 112.
  • the thermoelectric conversion layer 111 comes into contact with a member containing another metal material such as the bonding layer 112, the high temperature side electrode 15, the electrode 161 (low temperature side electrode 16 ), the element forming the thermoelectric conversion material is changed to the bonding layer 112 or the electrode ( The high temperature side electrode 15 and the low temperature side electrode 16) may diffuse, or the elements forming the bonding layer 112 and the electrode may diffuse into the thermoelectric conversion layer 111.
  • the diffusion prevention layer 113 suppresses the above diffusion and suppresses the deterioration of the thermoelectric conversion layer 111 due to the above diffusion.
  • the diffusion prevention layer 113 for example, at least one element selected from the group consisting of aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, molybdenum, silver and tantalum is preferable, and aluminum, titanium, More preferred is at least one element selected from the group consisting of chromium, iron, cobalt, nickel, zinc, molybdenum and tantalum.
  • a composite material in which two or more kinds of the above-mentioned forming materials are combined is preferable, and among the forming materials, a group consisting of aluminum, titanium, chromium, iron, cobalt, nickel, zinc, molybdenum and tantalum. A composite material in which two or more selected from the above are combined is more preferable.
  • the thickness of the diffusion prevention layer 113 is not particularly limited, but is preferably 0.5 ⁇ m or more and 100 ⁇ m or less, more preferably 0.1 ⁇ m or more and 50 ⁇ m or less.
  • the upper limit value and the lower limit value of the thickness of the diffusion prevention layer 113 can be arbitrarily combined.
  • the n-type thermoelectric conversion element 12 has a thermoelectric conversion layer 121. Further, as shown in the drawing, the n-type thermoelectric conversion element 12 may have a bonding layer 122 and a diffusion prevention layer 123.
  • the thermoelectric conversion layer 121 is an element that generates a thermoelectromotive force by moving a negatively charged electron (e ⁇ ) from a high temperature portion to a low temperature portion when a temperature difference occurs in the element.
  • the thermoelectric conversion layer 121 has an n-type electronic physical property and is formed using a thermoelectric conversion material having a negative Seebeck coefficient.
  • the thermoelectric conversion layer 121 is obtained by machining the thermoelectric conversion material of the present embodiment described above into a desired shape.
  • the thermoelectric conversion layer 121 has a columnar shape.
  • the compound of this embodiment can be a compound having p-type electronic properties or a compound having n-type electronic properties by changing the content of Sb or Bi contained in the compound to control the carrier density. ..
  • the electronic properties of the thermoelectric conversion material can be controlled by using the electronic properties of a compound having a desired electronic property as the material of the thermoelectric conversion material.
  • the bonding layer 122 is provided between the thermoelectric conversion layer 121 and the high temperature side electrode 15.
  • the joining layer 122 favorably joins the thermoelectric conversion layer 121 and the high temperature side electrode 15 electrically and mechanically. Thereby, the bonding layer 122 reduces the contact resistance between the thermoelectric conversion layer 121 and the high temperature side electrode 15.
  • the bonding layer 122 is provided between the thermoelectric conversion layer 121 and the electrode 162 (low temperature side electrode 16).
  • the joining layer 122 favorably joins the thermoelectric conversion layer 121 and the electrode 162 electrically and mechanically. Thereby, the bonding layer 122 reduces the contact resistance between the thermoelectric conversion layer 121 and the electrode 162.
  • the material for forming the bonding layer 122 and the thickness of the bonding layer 122 may be the same as those of the bonding layer 112 described above.
  • the diffusion prevention layer 123 is provided between the thermoelectric conversion layer 121 and the bonding layer 122.
  • the element constituting the thermoelectric conversion material diffuses into the bonding layer 122 or the electrodes (high temperature side electrode 15, low temperature side electrode 16), or the element constituting the bonding layer 122 or the electrode diffuses into the thermoelectric conversion layer 121. This suppresses deterioration of the thermoelectric conversion layer 121 due to diffusion.
  • the material for forming the diffusion prevention layer 123 and the thickness of the diffusion prevention layer 123 may be the same as those of the diffusion prevention layer 113 described above.
  • the p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 may have a protective film on the surface of the thermoelectric conversion element, which may come into contact with the gas in the environment where the thermoelectric conversion element is placed.
  • the thermoelectric conversion element by having the protective film, suppresses the reaction between the thermoelectric conversion material that the thermoelectric conversion element has, and the gas in the environment where the thermoelectric conversion element is placed, of the substance that can be generated from the thermoelectric conversion material. Diffusion can be suppressed.
  • the element contained in the protective film include silicon and oxygen.
  • the thickness of the protective film is not particularly limited, but is preferably 0.5 ⁇ m or more and 100 ⁇ m or less, more preferably 1 ⁇ m or more and 50 ⁇ m or less.
  • the high temperature side electrode 15 and the low temperature side electrode 16 are made of, for example, copper having high electrical conductivity and thermal conductivity.
  • the thermoelectric conversion device 10 has an insulating plate 17 that covers the high temperature side electrode 15.
  • the insulating plate 17 has a function of reinforcing the thermoelectric conversion device 10.
  • a ceramic plate such as alumina or aluminum nitride can be used.
  • the thermoelectric conversion device 10 has a heat dissipation plate 18 that covers the low temperature side electrode 16.
  • the heat dissipation plate 18 has a function of reinforcing the thermoelectric conversion device 10 and promoting heat dissipation from the thermoelectric conversion element. Since the thermoelectric conversion device 10 includes the heat dissipation plate 18, it is easy to form a temperature difference (temperature gradient) in the thermoelectric conversion element and to easily generate thermoelectromotive force.
  • an insulating ceramic plate such as alumina or aluminum nitride can be used.
  • thermoelectric conversion device 10 First, heat H is transmitted to the thermoelectric conversion device 10 from a heat source (not shown) arranged above the thermoelectric conversion device 10. Inside the thermoelectric conversion device 10, the heat H transferred from the insulating plate 17 to the high temperature side electrode 15 is further transferred to the upper part of the thermoelectric conversion element via the high temperature side electrode 15.
  • thermoelectric conversion device 10 the heat H of the thermoelectric conversion element is transmitted to the heat dissipation plate 18 via the low temperature side electrode 16.
  • the p-type thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 have a temperature gradient between the upper end and the lower end.
  • thermoelectric conversion element 11 In the p-type thermoelectric conversion element 11, holes (h + ) move from the high temperature upper end to the low temperature lower end to generate thermoelectromotive force. On the other hand, in the n-type thermoelectric conversion element 12, electrons (e ⁇ ) move from the upper end having a higher temperature to the lower end having a lower temperature to generate thermoelectromotive force.
  • the potential difference in the p-type thermoelectric conversion element 11 and the potential difference in the n-type thermoelectric conversion element 12 are opposite in the vertical direction.
  • thermoelectric conversion element 11 and the n-type thermoelectric conversion element 12 are directly connected. It can be a connected thermoelectric conversion device.
  • thermoelectric conversion device 10 the electromotive force between the electrodes 161 and 162 is the sum of the thermoelectromotive force of the p-type thermoelectric conversion element 11 and the thermoelectromotive force of the n-type thermoelectric conversion element 12.
  • a current I is generated from the electrode 162 toward the electrode 161.
  • thermoelectric conversion device 10 as described above can be used as a power source of the external load 50 by connecting the electrode 161 and the electrode 162 to the external load 50.
  • the external load 50 include a battery, a capacitor, a motor, etc. that are a part of an electric device.
  • thermoelectric conversion device 10 since the thermoelectric conversion element of the present embodiment is used as the material of the thermoelectric conversion element, the thermoelectric conversion device has excellent thermal efficiency in the high temperature region.
  • FIG. 2 is a schematic perspective view of a thermoelectric conversion module including the thermoelectric conversion device described above.
  • the thermoelectric conversion module 100 is a structure in which a plurality of thermoelectric conversion devices 10 are unitized.
  • the thermoelectric conversion module 100 has a plurality of thermoelectric conversion devices 10.
  • the plurality of thermoelectric conversion devices 10 are arranged in a grid pattern between the insulating plate 17 and the heat dissipation plate 18.
  • thermoelectric conversion module 100 a plurality of p-type thermoelectric conversion elements 11 and a plurality of n-type thermoelectric conversion elements 12 are alternately arranged in the directions A and B shown in the figure.
  • thermoelectric conversion elements 11 and the n-type thermoelectric conversion elements 12 are electrically connected in series using the high temperature side electrode 15 and the low temperature side electrode 16.
  • the thermoelectric conversion modules shown in the figure are connected in series as indicated by the chain double-dashed line ⁇ .
  • connection indicated by the chain double-dashed line in the figure is an example, and there are no particular restrictions on the connection method. It is preferable that all the p-type thermoelectric conversion elements 11 and the n-type thermoelectric conversion elements 12 are connected to each other alternately and in series via metal electrodes.
  • the output of the thermoelectric conversion module 100 is a value obtained by multiplying the output of the p-type thermoelectric conversion element 11 by the number of used p-type thermoelectric conversion elements 11, and the output of the n-type thermoelectric conversion element 12 is the number of used n-type thermoelectric conversion elements 12.
  • the value multiplied by is almost equal to the sum of. In order to increase the output of the thermoelectric conversion module 100, it is effective to increase the output of the thermoelectric conversion element or increase the number of thermoelectric conversion elements used.
  • the sum of the number of p-type thermoelectric conversion elements 11 and the number of n-type thermoelectric conversion elements 12 in the thermoelectric conversion module 100 can be appropriately changed according to conditions such as the size of the thermoelectric conversion module 100 and the electromotive force to be obtained.
  • the sum of the number of p-type thermoelectric conversion elements 11 and the number of n-type thermoelectric conversion elements 12 in the thermoelectric conversion module 100 is preferably 50 or more and 1000 or less, more preferably 50 or more and 500 or less, and 50 or more. More preferably, the number is 250 or more and 250 or less.
  • An external connection electrode 31 is connected to the lower end of the p-type thermoelectric conversion element 11 arranged at one end of the chain double-dashed line ⁇ .
  • An external connection electrode 32 is connected to the lower end of the n-type thermoelectric conversion element 12 arranged on the other end side of the chain double-dashed line ⁇ .
  • thermoelectric conversion module 100 the space between adjacent thermoelectric conversion elements may be filled with an insulating material.
  • an insulating material can reinforce the thermoelectric conversion module 100 and improve the durability of the thermoelectric conversion module 100.
  • the adjacent thermoelectric conversion elements may be separated from each other without filling the space between the adjacent thermoelectric conversion elements with an insulating material.
  • the heat transfer path when the heat H input to the thermoelectric conversion module 100 is transmitted from the insulating plate 17 to the heat dissipation plate 18 is a p-type thermoelectric conversion element 11 and an n-type thermoelectric conversion element. Limited to 12. Therefore, the heat H that is radiated without being input to the thermoelectric conversion element is unlikely to occur, and as a result, high thermoelectromotive force can be obtained.
  • thermoelectric conversion module 100 When heat H is input from above the thermoelectric conversion module 100, a current I is generated from the external connection electrode 31 to the external connection electrode 32.
  • thermoelectric conversion module 100 as described above uses the thermoelectric conversion device 10 described above, the thermoelectric conversion module has excellent thermal efficiency in a high temperature region.
  • Seebeck coefficient ⁇ [V/K] was calculated from the measured value by a thermoelectric property evaluation device ZEM-3 (manufactured by Advance Riko Co., Ltd.) according to JIS R1650-1.
  • the sample of the compound used for measurement was cut out using a diamond cutter.
  • the dimensions of the sample for measuring the Seebeck coefficient were 4 mm ⁇ 2 mm ⁇ 2 mm.
  • the R-type thermoelectric conversion pair used for temperature measurement and voltage measurement was fixed in contact with the long axis direction of the sample at an interval of 2.7 mm or 1.3 mm.
  • the sample was heated to a predetermined temperature in a helium gas atmosphere (0.01 MPa). Further, by heating one end of the sample, a temperature difference was made in the height direction of the sample. At this time, the temperature difference ( ⁇ T) and the voltage difference ( ⁇ V) between the R-type thermoelectric conversion pairs were measured. The temperature difference ( ⁇ T) was adjusted within the range of 0.5°C or higher and 10°C or lower.
  • the voltage difference ( ⁇ V) was measured when three different temperature differences ( ⁇ T) were given.
  • the Seebeck coefficient ⁇ was calculated from the slope of the voltage difference ( ⁇ V) with respect to the temperature difference ( ⁇ T).
  • the Seebeck coefficient was measured when it was determined that the temperature of the sample was stable according to the following criteria. (Evaluation criteria) The temperature of the sample was measured every 10 seconds in the thermoelectric property evaluation apparatus, and a moving average of 5 points was calculated for the latest 5 measurements. At that time, when the value of the 5-point moving average at a certain time is smaller than 0.5° C. as compared with the 5-point moving average of the latest 5 measurements 10 seconds before the time, the temperature of the sample is It was judged to be stable.
  • Resistivity The resistivity ⁇ [ ⁇ m] was measured by a DC four-terminal method using a thermoelectric property evaluation device (model number ZEM-3, manufactured by Advance Riko Co., Ltd.).
  • Thermal conductivity is calculated from the following equation from thermal diffusivity ⁇ [m 2 /s], heat capacity C p [J/g], and density d [g/m 3 ]. It was calculated using (4).
  • a sample of the compound used for measuring the thermal diffusivity ⁇ was cut out using a diamond cutter.
  • the dimensions of the sample for measuring the thermal diffusivity were 4 mm x 4 mm x 0.5 mm.
  • thermal diffusivity The thermal diffusivity ⁇ was measured using a laser flash analyzer LFA457 MicroFlac (manufactured by NETZSCH). At the time of measurement, the surface of the sample was coated in black with carbon spray Graphite 33 (manufactured by CRC industries Europe).
  • Capacity capacity C p was measured using EXSTAR DSC 7020 (manufactured by SII Nano Technology Inc.). The dimensions of the sample for measuring the heat capacity were 4 mm ⁇ 4 mm ⁇ 0.5 mm.
  • Density The density d was measured at room temperature using a density measurement kit (manufactured by METTLER TOLEDO) with the Archimedes method using water as the measurement principle. The size of the sample for measuring the density was 7 mm ⁇ 4 mm ⁇ 4 mm.
  • thermoelectric conversion performance index z Thermoelectric conversion performance index z[1/K] is expressed as zT by the Seebeck coefficient ⁇ [V/K] at the absolute temperature T, the resistivity ⁇ [ ⁇ m], and the thermal conductivity ⁇ [W/(m ⁇ K)]. was calculated using the following formula (2).
  • Crystal Structure Analysis The crystal structure of the compound was measured by powder X-ray diffraction under the following conditions using a powder X-ray diffraction measurement device X'Pert PRO MPD (manufactured by Spectris Co., Ltd.), and the obtained powder X-ray diffraction pattern was obtained. It was obtained by analysis.
  • Measuring device powder X-ray diffraction measuring device X'Pert PRO MPD (manufactured by Spectris Co., Ltd.)
  • X-ray generator CuK ⁇ ray source, voltage 45 kV, current 40 mA
  • Slit slit width 10mm
  • Sample preparation Powdering by mortar crushing
  • Sample stage Dedicated glass substrate Depth 0.2 mm
  • composition distribution of the compound was measured under the following conditions using a scanning electron microscope JEOL JSM-5500 (manufactured by JEOL) equipped with an energy dispersive X-ray spectrometer JED-2300 (manufactured by JEOL Ltd.). Sought by doing.
  • SEM JEOL JSM-5500 (made by JEOL) Acceleration voltage 20kV, current 65 ⁇ A EDX: JED-2300 (made by JEOL Ltd.)
  • Analysis software Analysis station
  • Carrier Density The carrier density p [cm ⁇ 3 ] was determined by 5-terminal hole measurement using a physical property measuring device PPMS (manufactured by Quantum Desig) and a dedicated DC resistance sample pack. The dimensions of the sample for measuring the Seebeck coefficient were 6 mm ⁇ 2 mm ⁇ 0.4 mm.
  • the rate of change in resistivity of the compound before and after heating and cooling was measured by the above-described method for measuring resistivity and evaluated by the following procedure.
  • (1) The resistivity of the compound was measured at 100° C. as the resistivity ⁇ (Before) before the heating test.
  • the resistivity was measured at 100° C. as the resistivity ⁇ (After) after the heating test.
  • the typical rate of temperature increase/decrease was ⁇ 50°C/min.
  • the typical time required for measurement in the temperature rising process from 100° C. to 500° C. was 3 hours, and the typical time required for measurement in the temperature decreasing process from 500° C. to 100° C. was 2 hours.
  • Examples 1 to 10 and Comparative Examples 1 to 3 The compounds of Examples 1 to 10 and Comparative Examples 1 to 3 were produced by the production method of the third embodiment described above.
  • Each raw material was weighed and mixed at the composition ratio (molar ratio) shown in Table 1 below to obtain a mixture. Then, 3.0 g of the mixture was put into a quartz ampoule (hemispherical bottom type, inner diameter 6 mm, outer diameter 8 mm) and sealed under a reduced pressure of 1 ⁇ 10 ⁇ 3 Pa or less. The quartz ampoule was heated to 950° C. in an electric furnace to melt the mixture.
  • the quartz ampoule was taken out of the electric furnace at 950°C and immediately put in water at room temperature. By this operation, the melt in the quartz ampoule was rapidly cooled and solidified. In the quenching step, the melt at 950° C. was cooled to 100° C. or lower within 1 minute. The solidified material in which the melt solidified was recovered from the quartz ampoule.
  • the obtained solidified material was crushed into a mortar to obtain a material powder.
  • the material powder was packed in a dedicated carbon die and spark plasma sintered under the following conditions.
  • the sintered material powder was quenched by stopping the plasma discharge, and the target compound was obtained.
  • Table 1 shows the compositions of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • FIG. 3 is a powder X-ray diffraction pattern of the compound of Example 1.
  • the crystal structures of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3 were all assigned to Fm-3m and found to be cubic, and the main phase was SnTe.
  • FIG. 4 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • FIG. 5 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 1-10 and Comparative Examples 1-3.
  • FIG. 6 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • FIG. 7 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • FIG. 8 is a graph showing the temperature dependence of zT of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3.
  • FIG. 9 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 1 and 2.
  • FIG. 10 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 1 and 2.
  • FIG. 11 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 1 and 2.
  • FIG. 12 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Examples 1 and 2.
  • FIG. 13 is a graph showing the temperature dependence of zT of the compounds of Examples 1 and 2.
  • Example 1 Comparing Example 1 and Example 2, it can be seen that the Seebeck coefficient is improved by replacing Sn with In. In particular, the improvement of the Seebeck coefficient at 400° C. or lower is remarkable. Further, it can be seen that the thermal conductivity is reduced by replacing Sn with In.
  • FIG. 14 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 2 and 4.
  • FIG. 15 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 2 and 4.
  • FIG. 16 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 2 and 4.
  • FIG. 17 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Examples 2 and 4.
  • FIG. 18 is a graph showing the temperature dependence of zT of the compounds of Examples 2 and 4.
  • Example 2 Comparing Example 2 and Example 4, it can be seen that the thermal conductivity is lowered by replacing Sn with Cu.
  • FIG. 19 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • FIG. 20 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • FIG. 21 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • FIG. 22 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • FIG. 23 is a graph showing the temperature dependence of zT of the compounds of Examples 4, 8, 9 and Comparative Example 1.
  • FIG. 24 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Example 2 and Comparative Example 1.
  • FIG. 25 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Example 2 and Comparative Example 1.
  • FIG. 26 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Example 2 and Comparative Example 1.
  • FIG. 27 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Example 2 and Comparative Example 1.
  • FIG. 28 is a graph showing the temperature dependence of zT of the compounds of Example 2 and Comparative Example 1.
  • FIG. 29 is a graph showing the temperature dependence of the Seebeck coefficient ⁇ of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • FIG. 30 is a graph showing the temperature dependence of the resistivity ⁇ of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • FIG. 31 is a graph showing the temperature dependence of the thermal conductivity ⁇ of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • FIG. 32 is a graph showing the temperature dependence of the output factor (Power Factor) of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • FIG. 33 is a graph showing the temperature dependence of zT of the compounds of Examples 1, 5 to 7 and Comparative Examples 1 and 3.
  • Table 2 shows the resistivity of the compounds of Examples 1 to 10 and Comparative Examples 1 to 3 before heating, the resistivity after heating at 500° C., and the rate of change of the resistivity.
  • Table 3 shows the carrier densities of the compounds of Examples 1, 2, 5 to 7.
  • Example 2 Comparing Example 1 and Example 2, the compound in which Sn of SnTe is replaced by Mn, Bi and Cu (Example 2) is further replaced by In by replacing Sn (Example 1). It can be seen that the absolute value of the rate of change of the rate decreases.
  • Example 4 a graph showing a change in resistivity during heating and cooling is shown.
  • FIG. 34 is a graph showing the results of evaluation of thermal history of resistivity of the compound of Example 4.
  • FIG. 35 is a graph showing the results of evaluation of the thermal history of resistivity of the compound of Comparative Example 1.
  • the compound of the present invention has a small absolute value of the rate of change in resistivity before and after heating and cooling, it can be applied to various fields such as in-vehicle use.
  • thermoelectric conversion device 11... P-type thermoelectric conversion element, 12... N-type thermoelectric conversion element, 15... High temperature side electrode, 16... Low temperature side electrode, 17... Insulating plate, 18... Radiating plate, 31... External connection electrode, 32... External connection electrode, 50... External load, 100... Thermoelectric conversion module, 111, 121... Thermoelectric conversion layer, 112, 122... Bonding layer, 113, 123... Diffusion prevention layer, 161... Electrode (low temperature side electrode), 162 ... Electrode (low temperature side electrode)

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  • Organic Chemistry (AREA)
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  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)

Abstract

L'invention concerne un composé qui comprend Sn, Te et Mn, et qui comprend en outre Sb et/ou Bi.
PCT/JP2019/047017 2018-12-04 2019-12-02 Composé, et matériau de conversion thermoélectrique WO2020116388A1 (fr)

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JP2011514666A (ja) * 2008-02-07 2011-05-06 ビーエーエスエフ ソシエタス・ヨーロピア 熱電応用のためのドープテルル化スズを含む半導体材料
JP2013219095A (ja) * 2012-04-05 2013-10-24 Toyota Industries Corp 熱電材料及びその製造方法
JP2014520202A (ja) * 2011-05-13 2014-08-21 エルジー・ケム・リミテッド 新規な化合物半導体及びその活用

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DE2113676C2 (de) * 1971-03-20 1985-09-12 Conradty GmbH & Co Metallelektroden KG, 8505 Röthenbach Elektrode für elektrochemische Prozesse
CN103400932B (zh) * 2008-08-29 2016-08-10 Lg化学株式会社 新型热电转换材料及其制备方法，以及使用该新型热电转换材料的热电转换元件

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JP2011514666A (ja) * 2008-02-07 2011-05-06 ビーエーエスエフ ソシエタス・ヨーロピア 熱電応用のためのドープテルル化スズを含む半導体材料
JP2014520202A (ja) * 2011-05-13 2014-08-21 エルジー・ケム・リミテッド 新規な化合物半導体及びその活用
JP2013219095A (ja) * 2012-04-05 2013-10-24 Toyota Industries Corp 熱電材料及びその製造方法

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US20220033273A1 (en) 2022-02-03

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